Problem: In $45$ years, Gabriela will be $4$ times as old as she is right now. How old is she right now?
Solution: We can use the given information to write down an equation about Gabriela's age. Let Gabriela's age be $g$. In $45$ years, she will be $g + 45$ years old. At that time, she will also be $4 g$ years old. Writing this information as an equation, we get: $g + 45 = 4 g$ Solving for $g$, we get: $3 g = 45$. $g = 15$.